1. Field of Invention
This invention relates generally to linear stepper motors and, more particularly, to a method of splicing the platen component of a linear stepper motor to increase its range of travel.
The linear stepper motor is well known in the prior art and operates upon established principles of magnetic theory. The stator or platen component of the linear stepper motor consists of an elongated, rectangular steel bar having a plurality of parallel teeth that extends over the distance to be traversed and functions in the manner of a track for the so-called forcer component of the motor.
The platen is entirely passive during operation of the motor and all magnets and electromagnets are incorporated into the forcer or armature component. The forcer moves bi-directionally along the platen assuming discrete locations in response to the state of the electrical current in its field windings.
Such a linear stepper motor can be utilized to perform various functions and is particularly well adapted for use as a precision linear measuring device over extended distances.
A problem arises in that the platens are manufactured in fixed lengths and because of the size limitations of the manufacturing equipment, the maximum size that can be produced by conventional methods is 144 inches. However, in many industrial applications it would be desirable to have a precision linear measurement device based on a linear motor which would perform accurately up to 300 inches or more.
Thus, the present invention has been developed to provide a method of splicing platen components together to extend their length while maintaining the positional accuracy of the motor and the integrity of the magnetic flux field necessary for proper operation of the forcer component of the motor.
2. Description of Related Prior Art
A printed publication entitled, LX Indexer/Drive User Guide prepared by the Compumotor Division, Parker Hannifin Corporation discloses the theory of operation for a linear stepping motor.